Tires are known for land transport means with two or more wheels, such as for example bicycles, motor cycles or suchlike, both for sport and amateur use and also for daily use, which for each of the wheels comprise a tire disposed in contact with the ground and mounted on rims, and a corresponding air chamber.
This conventional solution, in some circumstances, as for example regarding the use of mountain bikes, cycles, motor cycles and/or in other situations, mostly in competitive sport, is not always the best for users regarding the inflation pressure. Indeed, if for traveling over certain ground, for example with poor adherence, a lower inflation pressure is advised, this can contrast with the need to safeguard the rims when there are obstacles such as sidewalks, curbs or other.
To meet these requirements, in the production of tires, double chamber tires have been developed, with different inflation pressures. In particular, a first air chamber can be positioned adherent to the rim and a second air chamber can be made in the space between the first air chamber and the tire. This configuration allows to reduce the bulk of the two air chambers, equating them in size to the technologies that use a single air chamber. An air chamber valve can be associated to each air chamber, accessible for the user with inflation tools and which allows to inflate them to different pressures.
The possibility of defining two zones at different pressures can influence the protection of the rim from damage and the driving performance of the means.
In particular, the first air chamber, nearer the rim, can be inflated to high pressure (for example 100 psi) and can act as a shock absorber and prevent damage to the rim in the case of jumps and uneven ground, or obstacles. Another advantage of keeping a high pressure in the first air chamber is that it allows an optimum connection between the tire and the rim without them being distant from each other.
However, in order to improve driving conditions, especially off-road, it is common practice to lower the pressure in the air chamber for example to 0-10 psi in order to increase the area of contact between ground and tire. In the double air chamber systems described, this can be achieved by acting on the pressure in the second air chamber, leaving the pressure in the first air chamber unchanged. In particular, the pressure in the second chamber is taken to these conditions of low pressure because it is the portion of the air chamber that directly affects adherence to the ground.
The presence of two air chambers that can be inflated to different pressures allows to identify two volumes that exploit the advantages deriving from using high and low pressures together. However, this technology provides to install one valve for each air chamber. In this way there is a possible increased cost for the producer, since the cost of the valve greatly affects the overall cost of the tire; moreover, the rims currently on the market have to be modified to house the two valves, and there is a greater inflation time due to the need to move from one valve to the other. Finally, there may be unbalanced weight on the rim due to housing two distinct valves.
Document DE-A-106448 describes a valve for the passage of air between two air chambers of a known type.
Document U.S. Pat. No. 2,549,075 describes a valve for double chamber tires. The valve has two outlets for both the air chambers, or one outlet for a single chamber. Consequently, this known solution does not allow to selectively inflate one air chamber or the other.
Document U.S. Pat. No. 2,991,821 describes a valve for compartmentalized tires with two air chambers.
Document U.S. Pat. No. 3,536,119 describes a dual valve for known tires.
Document US-A-2010/0108217 describes a system of valves for tires with a double air chamber that functions as a two-way selector tap.
There is therefore a need to perfect a valve for air chambers that can overcome at least one of the disadvantages of the state of the art.
In particular, one purpose of the present invention is to obtain a single valve that can interact with a double chamber tire where it is not necessary to have two valves, one for each chamber.
Another purpose of the present invention is to obtain a valve for tires with two air chambers that is simple to use, with a possible production cost that is lower than current alternatives and/or with a possible overall weight less than current alternatives.
The Applicant has devised, tested and embodied the present invention to overcome the shortcomings of the state of the art and to obtain these and other purposes and advantages.